Tunnel



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' Application med December 31, 1927. Serial `No.`2443,981.

' My invention relates to tunnels.,v and par ticularly to that portion of a tunnel structure- Whichmight, perhaps, .be best designated as theapproach.- vIt relates especially to approaches forvehicular tunnels which must 4the river and the minimum possible depth of the tunnell are such that very. long ap-v preaches are necessary in order-to obtain a suitable grade. '-A .1r ,r-ain where the natural topography lis such that no unusual diii'- culties are presented, the land on either sideI .of the river, under or through which the approaches must be constructed, includes closely.

built upl portions of a city sotthat the cost I Vofacquiring the necessary right of way is ,minimum of enormous. lIn such cases and many othersl too, an 'approach of such design .that the entire structure can be built within two or threehundred feet of the entrance to the tunnel proper will represent a substantial reduction in the cost' of tunnel construction.

The primary 'obj ect of this invention, therefore, is to .provide an approach occupying a tunnel proper, and which will. provide an approach,y to -and exit from-the v.tunnel on substantially anyI desired grade.. .Another ob- .ject is tojprovide an approach whichinay be utilized as thefoundation for a building of' any' type'so that the full use ofvaluable land is substantially preserved and the land, in

fact, may be put to a double use. 4

With these vobjects in view my invention includes-.the novel elements and the combinations and arrangements ofthe elements described below and illustrated in a more or les'sfetypical manner in thel accompanying Fig. l 1s a partial, vertical section in the-v broken p1ane. 1-1 of Fig. 27of a tunnel with its approaches; v.

Figli; in the broken plane 2-`2;

'.Fig. '3 represents aportion of a helicoidal surface in which the elements areperpendicular tothe linear directrix; v

olmd space, which may -be constructed su tantially at`.the endo 'the 2- is a partial, horizontal section ofA Fig. 4 represents'a-.portionof a helicoidal surface, the upperp-art ofwhich is concave, and in which the 'elernentsare downwardly inclined toward the linear directrix; Fig. -5 is a fragmentary horizontal sect-ion of a modified torn-lof approach;

' Fig. 6 is a frontelevation view of an appreach of a somewhat different type than that shown Figs. l and 2, and having enrtrancesat different elevations;

Fig. is a half-planl view of the approach v shown 1n Fig. 6 showing a portion ef the street;

Fig. 8 is a section inthe plane 8$-8 of Fig. 7; and Y Fig. 9 isa section of the tunnel which would be used with an approach of the character shown in Figs. 6, 7 and 8.,

Referring to the drawings, '1 represents the surfaceof the water in the river, 2 represents the bed, and Srepresents the tunnel beneath the bed of the river. In the diaW- ings, I have shown this tunnel as level, but.

it is-to be understood that it may be constructed on any desired grade or grades.

Where the landV slopes rapidly upward froin the bank of the river, or .where 'the land..-

is. closely built up, asin a city, or-in' other cases if desirable, I propose to construct approaches'to the tunnelpropeif. comprising helicoidal surfaces in which the lhelical di rectrices'have such al pitch as will give thev desired grade. The elements of the helicoidal surfaces may belnormal to the linear direc' trices, or may beinclined thereto at any de .sired angle. For eXample,"inFigs. 3 an'd 4,

4 represents the plan lview of a helical direcelevation view fof the linear 'directrix and the plan4 view yis the po1nt, 7. Using these two directrices, thehehcal surface may berenv erated by,'orn1`ay comprise elements, 8, which 1 are perpendicular tothe linear di-recti'ix,'6, at

various points and toucher-intersect the heli-l I- I cal directrix, 5. j

In order to counterbalan the centrifugal force developed by avehic moving karound upon the 'surface vof the helle from thehelical directrixfto'the linear directrix, asshown in Fig.' ,This will produce va concave or bankedif `helicoidal .surface which is the preferred form.A

In lthe actual construction .of these ap# p d, the surface may be' generatedv'by', or" mayoomprise ele,

ments, 9. which'.are" "downwardly inclined 105 proaches a central shaft, 10, of the desired diameter, is constructed.v In the drawings', this shaft is shown as cylindrical but 1115,15', of

-structed about theshaft, 10, and spaced therecourse, be of almost any other desired shape.`

"Depending upon the width of the roadway desired,`a second shaft or'wall,` 11, is confrom a v4distance equal to the width of the i directrix'of the desired pitch may be imag-v Ila ined to exist on the interior of the cylindrical wall, l1, and the helicoidal surface is generated by elementswhich intersect this helix scending double surfaces, one above ythe other which.

" figures,

and the axis, 13, of the inner shaft. The enf tire helicoid is, of course, not const-ructed but only that portion included between the inner and outer shafts. Such a helicoidal surface is shown vat 14.

In Figs." 1 and 2 I have illustrated this surface as making two 'complete turns in defrom the street level, 15, to. the tunnel level, 16. In other words, a vehicleen- `ters vand leaves any approach while moving in the same direction. This, of course, is not essential, as the descent or ascent maybe made at any desired grade and the entrance from the street to the helicoid and the exit from the helicoid to the tunnel may be ar-V ranged in any desired manner. y

' Referring particularly to Figs. 6, 7, 8 and 9 I' have illustrated approaches and exits at different levels. In other words, .instead of having a single helicoidal surface forming a comparatively wide roadway, I have shown are -quite analogous to what is commonly known `as a'double threaded screw. In these 17 represents the normal street level from'which entrance may be had to the lower helicoid, 18. The street may be divided by a wall, 19, which will serve tofretain inclined approaches or ramps, 20, leading to theentrance, 21, to the upper helicoid, 22. The exits opening into the tunnel, are shown at,

f 'y 23 and 24, and the tunnel itself has two pas'-v fs'ages, 25and 26, as shown in Fi If desired, openings, 27, may ie provided in the central shaft togive light and ventilation. It is contemplated, however, that'the ap roaches will be used asy foundations' for bulldings, and where this is the case, it would probably be desirable to cover the openings with glass so that noxious -gases would not arise therefrom into the court of the building.

I have shown no general scheme for vene tilating the tunnel and itis to be understood that any system may be used.

AMy preferred form of approach is shown in Fig. 5. Here, a sort ofsafety zone 28, would be provided at each corner upon which disabledl vehicles might be run or drawn to Thisl outer wall orshaft n get them out of the way of traffic and thus. avoid' congestion. In this -typeventilating and equipped kwith' suitable suction fans or 'blowers whereby :the gases discharged by motor vehicles may be .withdrawn from the tunnelv and approaches and fresh air sup plied.

. While I haveidescribed the general character of thel roadway surface in my approaches as helicoidah it is to be understood that this term is used only in a-descriptive sense as most nearly defining the actual structure which would be built. Where the elements of the helicoid are horizontal no difficulty will be encountered in making 'a smooth connection between the helicoid and the horizontal floors of the tunnel and driveway from the street, respectively. I Where the elements of thehelicoid are inclined to the linear directrix, it will be necessary to shafts, 29,- maybe provided. in the corners connection, and this surface may be a hyper-V at the juncture, with the helicoid to make a perfectly smooth connection.

Vhile I have illustrated and described my invention only in its preferred embodiment, itis to'be understood that the words which I havensed are words of description rather than words of limitation, and that changes, substantially within the purview of the appended claims, may be made without departing from the true scope and spirit of' my invention in its broader aspects.

What 4I claim is- 1. The combination with tunnel havinga plurality of passages at different elevations, of approaches to said passages comprising a plurality of separate helicoidal surfaces.

2. The combination withia tunnel having a plurality of passages at different eleva'- tions, ofapproaches to said'passages com prising a plurality of vertically disposed helicoidal surfaces. y

3. A tunnel approach comprising an inner shaft, an outer shaft, and aplurality of sep- -bolic paraboloid slightly modified perhaps drical inner sha t, a rectangular outer shaft,

and a helicoidal surfaceextending between and supported by said shafts to form an inclined approach to said tunnel having Zones.

of maximum width at the corners of the outer shaft.

5. A tunnel approach comprising an inner vertical shaft, an outer vertical shaft having some portions thereof spaced at greater distances from the inner shaft than other` portions, and a helicoidal surface extending between'said shafts to f'orm an inclined approach to said tunnel.

6..'.Ihe structure specified in claim 5 in CII which the elements of the helicoidal surface are downwardly inclined toward the inner shaft; whereby a banked, circular approach to the tunnel is provided.

7. A tunnel approach comprising an inner Vertical shaft, an outer vertical shaft having some portions thereof spaced at greater distances from the inner'shaft than other p0rtions7 and a plurality of helicoidal surfaces extending between said shafts to form sep- 10 arate inclined approaches to the tunnel; the elements of the helicoids bein@- downwardly inclined toward the inner shaft.

JAMES ELLICOTT HEWES. 

